Apparatus for fusion electrolyses



June 30, 1959 G. WENDT ETAL APPARATUS FOR FUSION ELECTROLYSES Filed March 1, 1955 Q MQ .MQ S

,NN m@ of the furnace.

arrakarvsroa avalan ELEQTRQLYSES Gnther Wendt, Toging (Inn), and Gnter bermann, 'Grevenbroich (Lower/Rhine), Germany, assignors to Vereinigte Aluminium-Werke, 150.1111, Germany Claims prinrity,.application Germany March le, 1954. 1.01 (Cla @Q4-e244).

aaipaaleatralysesf.,

The object of the,A invention is,v in, some points to im prove upon the process and apparatus as set forth in the .co-pending Vapplication of Lebrecht et al., Serial. No. 423,728, tiled April 16,195.4 for Brocess for Carrying Out Fusion Electrolyses, now abandoned. In said application the reduction of magnetic elds in an electrolytic furnace is accomplished by arranging rising conductors and the bus bars for the anodes and cathodes divided each in at least two parts, the parts being arranged from one another in such a manner that the rising conductors are substantially in the middle between two neighbouring cells and that the pair of cathode rails and the pair of anode rails are obliquely symmetrical with respect to the centre of the cell, using currents of 30,000 amperes and more.

As to furnaces supplied with currents of 50,000 amperes and more, it has now been found that the formation of magnetic fields in the metal melt and the electrolyte can be more effectively reduced by shielding the bus bars. Such shielding is so effective that the exact spacing and symmetry required in the aforesaid application is no longer absolutely necessary. This results in a savings of construction costs, as well as an improved melting process.

The means by which the object of the invention is obtained is described more fully with reference to the accompanying drawings, in which:

Figure 1 is a longitudinal cross-sectional view through a plurality of furnaces conducted in parallel,

Figure 1a is an enlarged modified form of a detail of Figure 1;

Figures 1b and 1c are cross-sectional views through types of shielding prole irons; and

Figure 2 is a cross-sectional view through Figure 1.

As in the aforesaid application, Serial No. 423,728, the furnace is provided with current from vertical bus bars 1, which are disposed symmetrically to the vertical, longitudinal and transverse axes of the furnace, as indicated by the distances a, b, and c. The horizontal anode bus bars 2 and the cathode bus bars 3 are symmetrically positioned with respect to the horizontal surface 4 of the metal melt. Non-magnetic conductors 5 connect the bus bars 2 to the anodes 6, while non-magnetic conductors 7 connect the cathodes 8 to bus bars 3. The supporting beams 9 have a shielding effect, as stated in the aforesaid application, Serial No. 423,728.

The furnace is shielded from anode bus bars 2 by means of iron plates 10, which as shown are wedgeshaped in section and extend over about two-thirds of the length of bus bars 2, and approximately over half The plates 10 may be of iron, and the apex of the wedge section is disposed over approximately .the center of the furnace. Instead of this cross section, various smaller plates may be mounted longitudinally extending different distances under the bus bars 2 as shown Thisiamatiqa relates@ a. precast. and apparatus` tar United States Patent O ffice gather. 'allthaaurraet 2,892,767 l?a.telitsatl` June 30, 1959 ia Figura la. the disturbances at tha vertical bas bar side being small and increasing toward themildle of the furnace, It haa been, established that in. a furnace havias. twa aged@ has bars lying clpaaly. side by Sida. the anode bus bar Shielding algassuiient to reduce arching of the metal, frena` 14 un.. te leas than 1 am If they lldutots S. are ferrmasnatimaterial, these @ganadera wlaah generally leasing aliada ald inta the furnace, maybe maenetigallyf ahortfcircuited by. ferro.- masnetia material.` .fer example irma aanneming plates, in, Sash a. inaugurar.YY that the. eurent ,Supp/liesv originating fram. an. aaosahas bar an. the right., aasi 0a the left,` are 'eaaneatad together. ia each. '1f only aaa aliada bus bar, Navidad. 0r the bus bara. are Placed Clase f0- Qsdut ra are, congested. together bly. ima Q ,1,1.1,1.aatas,.al4 over antralsngth of the furnace but`advantageously over the greater part at the, aged@ bus, bass far @gemela fwafthirda 0f 'the lrfilatla` @karaat bgaiaais a: f

`In the last third of the'fww bar eld counteracts the field of the anode itself. It is, therefore, important for the anode bus bar field at this point to project into the furnace as far as possible in order to cancel the arch producing field in the furnace. This is done by mounting an iron reflecting plate 11 over the bus bars 2, these plates extending over approximately onefourth of the length of the furnace and over an area not covered by plates 10. Consequently, a part of the external magnetic lield is utilized in order to reduce still further the internal field of the melt itself.

Instead of using at plates, profile irons such as angle irons or channels may be used as shown in Figures 1b and lc, in which instance the open side of the elements are kept upwardly directed. The ends of the furnace are shielded from vertical bus bars 1 by means of plates 12 and 13 which are placed as close as possible to the ends of the furnace. This type of shielding can sometimes be used alone to advantage, particularly when the distance between the vertical bus bar and the furnace is very small.

As indicated by dashed lines in Figure 2, if two anode bus bars are placed relatively close together, they can be regarded as one conductor, and the shielding effected by a single iron plate 10a or the like.

If gas collecting hoods are used to collect the furnace exhaust gases, they are preferably formed in one piece, or from parts which are joined so as to produce a satisfactory magnetically conducting unit. This permits a vgreat reduction in the magnetic fields and in the arching as compared to furnaces having hood parts joined in the usual manner by bolts with the joints sealed by a few millimeters of asbestos.

The thickness and the exact location of the shielding may be different for each type of furnace. The eiciency of the shielding can be easily checked by magnetic eld measurements for furnaces having pre-burned anodes, so that the shielding can be accordingly provided. In the case of the end furnace in a series line of furnaces in which there is no vertical bus bar to a following furnace, the shielding is varied advantageously somewhat in comparison to that herein described. As a -rule the shielding for the end furnace should not extend over two-thirds of the length of the horizontal anode bus bars, but only over the first half of the furnace.

Having now described the means by which the objects of the invention are obtained, we claim:

1. An electrolytic furnace for carrying out fusion electrolyses comprising an open top vessel, vertical bus bars at the ends of the vessel joined to horizontal anode bus bars extending above the vessel, a cathode in the bottom of the vessel, horizontal cathode bus bars beneath said vessel, with all of said bus bars and cathode being symmetrically arranged with respect to said cathode in order to damp magnetic elds in said vessel, and iron plates mounted longitudinally beneath said anode bus bars and above said vessel to shield said vessel from interfering magnetic elds. y v

2. An electrolytic furnace as in claim 1, said iron plates being wedge-shaped'in section and decreasing in thickness toward the center of said vessel.

3.'Ane1ectrolytic furnace as in claim 2, further com prisingY a plurality of equal strength iron plates longitudinally extending dierent .distances increasingly greater toward'the center ofsaid vessel.

4. An electrolytic furnace as in claim 3, further'c'omprising mounting the iron plates adjacent said vertical bus bars as closelygas possible to the ends of said vessel.

5. An electrolytic furnace as in claim 4, further comprising iron plates above the anode bus bars and said vessel extending over about one-fourth of the bus bar lead-out end of said vessel not covered lby said iron plate shields.

6. An electrolytc furnace as in claim 5, said iron plates further comprising profile irons having their open side directed toward said bus bars.

7. An electrolytic furnace as in claim 6. further comprising a magnetically conducting gas collecting hood mounted above said vessel.

8. An electrolytic furnace as in claim 7, further comprising a single iron plate for shielding a plurality of closely spaced anode bus bars taken as a single magnetic conductor.

9. An electrolytic furnace as in claim 1, said vessel being an end vessel in a series of connected vessels, and said iron plates extending over about one-half of the lead-in portion of said end vessel.

10. An electrolytic furnace as in claim 1, said iron plates extending from the lead-in vertical bus bar end of the vessel to about two-thirds the length of the vessel.

References Cited in the file of this patent FOREIGN PATENTS France Nov. 3, 1954 Australia Feb. 18, 1954 OTHER REFERENCES 

1. AN ELECTROLYTIC FURNACE FOR CARRYING OUT FUSION ELECTROLYSES COMPRISING AN OPEN TOP VESSEL, VERTICAL BUS BARS AT THE ENDS OF THE VESSEL, A HORIZONTAL ANODE BUS BARS EXTENDING ABOVE THE VESSEL, A CATHODE IN THE BOTTOM OF THE VESSEL, HORIZONTAL CATHODE BUS BARS BENEATH SAID VESSEL, WITH ALL OF SAID BUS BARS AND CATHODE BEING SYMMETRICALLY ARRANGED WITH RESPECT TO SAID CATHODE IN ORDER TO DAMP MAGNETIC FIELDS IN SAID VESSEL, AND IRON PLATES 